System and method for fast acquisition position reporting using communication satellite range measurement
First Claim
1. A location determination system, comprising a. a mobile terminal operative to take code phase measurements from signals received from a plurality of GPS satellites, said mobile terminal further being operative to receive a communication from a wireless signal communicating over an area of interest, said received communication enabling said mobile terminal to identify said area of interest;
- b. a communication satellite; and
c. a service operations center operative to receive said code phase measurements and an identification of said area of interest from said mobile terminal via said communication satellite, and to iteratively calculate a position solution using an initial position estimate based on said area of interest and said plurality of code phase measurements, wherein said area of interest has a size that is less than a size of a convergence zone of the position solution process using said iterative calculations.
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Accused Products
Abstract
A geographic tracking system with minimal power and size required at the mobile terminal collects observation data at the mobile terminal, forwards the data to a processor, which calculates the position. The mobile terminal needs only to gather a few milliseconds of observation data, and to relay this observation data to the processor. The range from the satellite (or other airborne transponder) to the terminal is determined using the known positions of an interrogating transmitter and a satellite, and a known terminal delay between the received signal and the transmission of the return signal, and the round trip time. An arc of locations is determined by computing an intersection of a sphere centered at the satellite having a radius given by the calculated range with a model of the Earth'"'"'s surface. The candidate points are considered and refined using code phase measurements from a set of GPS satellites. The candidate point having the lowest residuals or expected to measured code phases is chosen as the location of the mobile terminal. The measurements can be refined to account for various sources of error including measurement bias, relative motion and timing errors.
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Citations
18 Claims
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1. A location determination system, comprising
a. a mobile terminal operative to take code phase measurements from signals received from a plurality of GPS satellites, said mobile terminal further being operative to receive a communication from a wireless signal communicating over an area of interest, said received communication enabling said mobile terminal to identify said area of interest; -
b. a communication satellite; and
c. a service operations center operative to receive said code phase measurements and an identification of said area of interest from said mobile terminal via said communication satellite, and to iteratively calculate a position solution using an initial position estimate based on said area of interest and said plurality of code phase measurements, wherein said area of interest has a size that is less than a size of a convergence zone of the position solution process using said iterative calculations. - View Dependent Claims (2, 3, 4)
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5. A location determination system, comprising
a. a mobile terminal operative to take code phase measurements from signals received from a plurality of GPS satellites, said mobile terminal further being operative to receive a communication from a cellular signal communicating over an area of interest, said received communication enabling said mobile terminal to identify said area of interest; -
b. a communication satellite; and
c. a service operations center operative to receive said code phase measurements and an identification of said area of interest from said mobile terminal via said communication satellite, and to iteratively calculate a position solution using an initial position estimate based on said area of interest and said plurality of code phase measurements, wherein said area of interest has a size that is less than a size of a convergence zone of the position solution process using said iterative calculations. - View Dependent Claims (6)
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7. A location determination method in a service operations center, comprising:
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a. receiving a plurality of observation measurements taken from a respective plurality of GPS signals received by said mobile terminal;
b. receiving, from said mobile terminal via a satellite communication link, an identification of an area of interest in which said mobile terminal resides; and
c. iteratively calculating a position solution using an initial position estimate based on said area of interest and said plurality of observation measurements, wherein said area of interest has a size that is less than a size of a convergence zone of the position solution process using said iterative calculations. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18-35. -35. (canceled)
Specification